From ball screws to butterflies, valves are some of the hardest working and most reliable members of the process control and automation community. And just like those other components, many types of valves have been getting some serious technical makeovers in recent years—to the point that users often don't know about the helpful skills they've acquired.
However, some users are well aware of recent innovations in several primary valve technologies because they rely on them every day. For instance, Ineos Chlor is a major European producer of chlor-alkali and chlorine derivatives, and it recently reduced process variability by 5% at its plant in Runcorn, U.K., by replacing four traditional butterfly valves with Fisher Control-Disk valves from Emerson Process Management. This reduced variability, enabled the plant to increase throughput, avoid several unplanned shutdowns that could have cost a total of $600,000, and achieve a 96% overall equipment effectiveness (OEE) rating for the unit where the valves were installed (Figure 1).
"For a plant this size, even a modest reduction in variability can have a significant payback," explains Barry Makepeace, Ineos Chlor's control and instrumentation engineer. "Applying the Control-Disk valve not only saved us money, but also enabled us to optimize process control without sacrificing flow capacity or needing to re-pipe."
Runcorn previously used its butterfly valves to control the temperature and flow of cooling water to its primary condensers. Tight control is essential because if the condensers' temperature is too low, there will be residual chlorine in the system, which has to be removed. If the temperature is too high, there's an increased risk of a safety trip or plant shutdown. Each trip and subsequent unplanned shutdown can cost up to $100,000.
Unfortunately, the older valves had a small control range and a large dead band, which reduced their response to temperature changes. In the 12 months before replacing its valves, the plant experienced 23 trips and big production losses. However, adopting the Control-Disk valves provided a control range of 15 to 70% of travel, approaching the range of a segmented ball valve. This tighter, more reliable valve control enabled Runcorn's operators to optimize temperature set points and avoid at least six unplanned shutdowns.
Tank Farm Retrofit in Turkey
One of the most useful ways that recent valve innovations can be applied is in helping older systems gain a new lease on life. For example, the Tupras Izmit refinery in Kocael province, Turkey, recently undertook a major modernization program that included retrofitting more than 900 valves at the refinery's tank farms with Rotork's valve actuators and two-wire digital controls (Figure 2). Located near the Sea of Marmara, the 53-year-old refinery is the largest of four refineries operated by the Turkish Petroleum Refineries Co., and it produces more than 11 million tons of LPG, naphtha, gasoline, jet fuel, kerosene and diesel fuel annually.
Besides the retrofit, Tupras was also expanding and building new refinery facilities on an adjacent site with help from Técnicas Reunidas, an EPC contractor based in Madrid, Spain. This part of the overall project required more than 400 of Rotork's IQ electric actuators.
Back at the retrofit, Tupras Izmit is implementing Rotork's IQ intelligent, ATEX-certified explosion-proof, electric valve actuators to automate manually operated valves on the refinery's tanks. Nearly 800 of the compact actuators are being installed on existing valves, while 100 will consist of new, actuated valve packages, both of which are able to fit in tight spaces.
In addition, all of the valve actuators will be monitored and controlled via Rotork's Pakscan P3 two-wire digital bus network, which uses a proprietary, fast-update communications protocol, and has built-in redundancy for security. It provides a direct interface with host control and SCADA systems, while simplifying the overall control network, which optimizes actuator functionality and increases reliability. Pakscan can monitor and control up to 240 field units without repeaters at up to 20 kilometers. Because of Tupras Izmit's huge size, groups of IQ actuators in different areas will be monitored and controlled by 20 Pakscan P3 networks, each controlled by a Pakscan P3 master station, which provides a local center for monitoring and control and links the network to the site's SCADA system.
Meanwhile, non-intrusive hand-held interfaces with secure, bidirectional links are used to set control parameters, and commission and download integral data loggers. This system performs all switch setting and commissioning functions that traditionally were only performed by removing electrical covers. Using the multilingual menu on the actuators' display screens, valves can be quickly commissioned with or without main power connected. The same instrument can be used to download data to the IQ actuators, or upload diagnostics from their data loggers. These data loggers enable event-by-event histories of valve activity, including time- and date-stamped torque profiles produced during each opening and closing, to be generated. Using Rotork's IQ-Insight software on a PC, this data can be compared with valve torque signature profiles logged during commissioning to identify trends, such as valve operating wear.
Much of the retrofit is being carried out by Omas Teknik Pazarlama, which is based in Istanbul and represents Rotork in Turkey. Its responsibilities include design and fabrication of valve adaptations, installing the new actuators, commissioning and on-site support.
Pete Kundin, general manager of Rotork's eastern U.S. division, reports its smart actuators work with its free Insight 2 software, and enable users to access their data via several avenues. "Bluetooth or infrared devices can download data from our smart actuators, and then upload it to a PC running Insight 2," says Kundin. "Now our IQ3 actuators allow users to read operating data on a screen on the actuator itself. Finally, we've been gathering valve information via digital networks for 20 years, but valves still need six or seven control wires. However, two-wire, twisted-pair fieldbuses are getting more sophisticated, and our application-specific Pakscan fieldbus lets us put valves right on the network, and our Pakscan master station gateway lets us communicate via Modbus to other fieldbuses and Ethernet networks."
Also, Kundin reports that Rotork developed and launched two other recent innovations: control valve actuator (CVA) is an electric actuator that's more accurate than traditional, spring-diaphragm, pneumatic valve actuators and saves on air generation, and compact modulating actuator (CMA) is a more compact device for replacing legacy actuators. "We're even looking at developing triple-offset butterfly valves as a replacement for standard gate valves," he adds.
Long Distance, No Runaround
Another advantage enabled by recent valve innovations is that they're much better at networking with higher-level control and enterprise systems, which can save operators lots of time-consuming labor and travel. For instance, Santos is one of Australia's largest oil and gas suppliers, and it recently worked with Emerson Process Management to coordinate and improve upcoming operations across its $18.5-billion Gladstone LNG (GLNG) project in Queensland.
Emerson is the GLNG's main automation contractor (MAC), and it's providing equipment and expertise to help Santos gather and integrate real-time information from thousands of wells. Emerson technologies at the GLNG project include Fisher valves, Bettis actuators, Roxar multiphase meters, DeltaV digital automation system using CHARMS electronic marshalling, Rosemount measurement and analytical instruments, remote operations controllers and AMS Suite predictive maintenance software.
The pioneering project will convert coal seam gas to LNG for export to global markets. Gas from the Bowen and Surat Basins in eastern Queensland will be transported by a 420-kilometer, underground pipeline to an LNG plant on Curtis Island, located near Gladstone on the coast. Meanwhile, Santos' remote operations center in Brisbane is approximately 500 kilometers south of Gladstone, but it integrates data from GLNG's gas fields, pipelines and plant for real-time, 24/7 monitoring and collaboration with teams in the field. The GLNG project is on track to make its first LNG shipments in 2015, and initial capacity is planned to be 3 to 4 million tons per year.
Santos and Emerson collaborated to plan and equip the Brisbane remote operations center where management, engineers and planners can use real-time information from the intelligent field devices to anticipate issues, collaborate, improve decisions and take actions to maximize key performance indicators (KPIs). "We've developed a remote operations center that's changed the way our gas fields are operated in the Bowen and Surat basins," says Rob Simpson, Santos' general operations manager. "We now have the ability to centrally monitor the production and progress of our intelligent assets up to 1,000 kilometers apart."
Similarly, another recent valve advance from Emerson is its Multiport Flow Selector (MPFS), which is used for testing oil and gas well liquids during production. Before MPFS arrived, these requirements were accomplished by opening and closing a series of flow manifolds to individually test the constituents of a hydrocarbon flow from the wellhead. However, MPFS is a single, compact system with a rotating plug that allows the flow from one well to be diverted from production for testing, which reduces the required number of valves by two-thirds. When coupled with an Emerson Bettis electric valve actuator specifically designed for it, MPFS can precisely control the flow, and automatically switch diverted well flow remotely from a control network.
Wireless and Other Futures
Probably the biggest innovation bringing valves and users together is the ongoing emergence of wireless for delivering field data to control and enterprise applications. "Wireless means cost saving, more intelligence and better diagnostic capabilities," says John Hancill, Emerson's strategic marketing director for R&D in Emerson's rack-and-pinion actuators division. "We view our Smart Wireless capabilities as creating opportunity for customers to implement solutions that were previously operationally or cost-prohibitive. Also, Emerson's use of Wireless HART creates a flexible, secure and reliable network, but wireless also allows users to remove people from potentially hazardous environments. Finally, we're also partnering and solving customers' problems using wireless valve operating systems with pneumatic or electric actuators."